Torque amplifier



Feb. 17, 1942. P. sPEcHT TORQUE AMPLIFIER Filed Nov. 29, 1939 F I G. 5.

INVENTOR ATTORNEY.

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Patented Feb. 17, 1942 ".roRQUE AMPLIFIER Paul Specht,-Berlin-Lichtenrade, Germany, as-

signor to Siemens Apparate und Maschinen Gesellschaft mit beschrnkter Haftung, Berlin, Germany, a corporation of Germany Application November 2s, 1939, serial No. 306,166 In Germany October 26, 1938 (ci. zon-48) 6 Claims.

This invention relates to means for amplifying a control force, and more particularly to a bolometer apparatus.

Devices have -heretofore been .proposed for amplifying control forces by governing a resistance differential between two electrical conductors, for example, in bridge connection, the differential being governed by controlling a fluid iiow to each of saidconductrs',there being a temperature differential between the conductors and the fluid. Suitable amplifying means, for example, a servo-motor can be controlled by said bridge connection. However, such devices in order to be sensitive, are complicated and expensive, and further require elaborate and very delicate adjusting means. Also, prior apparatus of this character have required bulky screening members for avoiding the disturbing effect of stray currents of air upon the conductors.

One of the objects of the present invention is to provide novel means for amplifying or picking up a control force, which means are simple, in-` expensive, and rugged.

Another object of the invention is to provide novel means of the above character which may be easily controlled and adjusted. A further object is to provide novel means for amplifying a control force without a friction or inertia reaction of the parts thereof.

An additional object is to provide novel means for amplifying a control force, which means are not hypersensitive but which are highly efficient.

The above and further objects and novel features will more fully appear from the detailed description when the same is read in connection -with the accompanying drawing. It is to be expressly understood, however, that the drawing is for purposes of illustration'only and is not intended as a definition of the limits of the invention, reference for this latter purpose being had to the appended claims,

In the drawing, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a side eleva'tionpartly in section and can be employed with the second embodiment of the invention. Y

The forms of the invention illustrated in the accompanying drawing, by way of example, comprise means for amplifying a control force produced by a compass for governing the control surfaces of a vehicle such as an aircraft. The

amplification is accomplished by governing a temperature differential, and hence a resistance differential between a pair of electric conductor elements, for example, in bridge connection, there being a suitable servo-motor or other amplifying means operatively connectedhto the elements and responsive to changes in resistance differentials therein, the motor being for oontrolling a rudder. Each. of the conductor elements are mounted in the uid flow path'of a conduit, Athe latter merge adjacentva common inlet, there being thus formed a forked interconnection of the conduits. A flow regulator, or control member is mounted adjacent the forked interconnection in such a manner that the position thereof governs the ratio of the flows in the conduits. The control member is operatively connected to the member the displacement or movement of which is to be'measured, as above mentioned, for example, a compass.

In the form shown in Fig. 1 suitable electric conductors I0 and II are in bridge connection, for example, as shown in Fig. 2 with conductors I2, I2a, there being a bridge member or instrument I3 conventionally connected across the bridge comprising, e. g., a relay which is operatively connected to a servo-motor I4, the latter governing a rudder Ila of a vehicle such as an aircraft. 4

The relative resistances of conductors. I0 and II is governed by a device comprising a control member I5 which in the form illustrated in Fig. 1 is constituted by a wedge shaped element of triangular cross-section situated adjacent a common inlet I6 in a conduit element I1. One of the edges I5a of the wedge element is directed against the direction of fluid flow. Preferably member I5 in combination with diverging walls I8, I9 of element I1 forms a pair of conduits 20, 2I in forked connection, which conduits respectively direct a fluid flow therein to conductors I0 and II. AIn order to avoid the disturbing effects of stray air currents the conductors are preferably mounted in recesses 22, 23 separated by a center piece 24 in a frame member 25 which is removably secured to conduit element I1 by means of pins 26. The side walls of the recesses are suitably slanted and aerodynamically adapted to the walls erned by a compass lia, there being suitable means (not shown) for adjusting the position of said element to a desired course.

Suitable means are provided for producing a Ifluid ilow comprising, for example, a diaphragm air pump 28 having a diaphragm 29 beneath a converging nozzle 30 formed in a plate 3l, the diaphragm being in spaced relation to the plate and forming a chamber 32 therewith. The nozzle 30 is in register with inlet I6. Alternately energizable electro-magnets 33 are mounted on the side of the diaphragm opposite to the chamber 29 and are adapted for vibrating the diaphragm in a conventional manner for producing the fluid flow.

In operation, when the control element I is centralized relative to the center piece 2l the flow in both conduits is equal, the bridge is balanced and motor Il is de-energized. However, if. for example, the vehicle should depart from a predetermined course, the compass I5a will shift the element I5 away from the central position thereby changing the fluid flow ratio of the conduits and the temperature differential of conductors In, Il. The bridge will therefore become unbalanced in response to the amount and direction of the course departure, and the servo-motor I4 will angularly shift surface Ila to restore the compass and control element to their predetermined positions.

In the above embodiment the duct 30 is stationary and the member I5. which splits the current of fluid or cooling medium, is movable; conversely, it is possible to make the nozzle duct movable thereby constituting the nozzle duct a control member, and to flxedly mount the part which splits the current of cooling fluid. Such an embodiment is shown in Fig. 4 wherein a. wedge member 3l is stationarily mounted centrally beneath the center piece 2l.

Instead of employing a diaphragm pump, as above, a nozzle tube 35 is provided which is movably mounted beneath the wedge 34 in such a manner that it is shiftable in the direction of the arrows as shown in Fig. 4.

In operation the stream of fluid emitting from the nozzle 35 strikes against the edge of the wedge 34 such that, in a manner analogous to that of the first embodiment, the fluid flow fed to bolometer filaments I0, Il, via the branches of the forked conduits, is a function of the position of said nozzle relative to the dividing edge of the wedge 3l.

If the latter embodiment is employed for the picking up, measuring, or amplification of gyro movements it is possible to use the exhaust air, or ventilation air of the gyro for the fluid directed to the filaments I0, Il, thereby eliminating a separate fluid pump which otherwise would be necessary. Fig. 5 illustrates such a gyro and nozzle device wherein a gyro in a housing 36 having an exhaust nozzle 31 is mounted by means of trunnions 33 in a gimbal frame 39, the latter being conventionally mounted by means of trunnions 4U upon bearings 4l.

There is thus provided novel means for amplifying or indicating the magnitude of a control force. The means are extremely simple and strung in construction, and are inexpensive to manufacture. The apparatus provides a reactionless pick-up of control or adjusting forces and is applicable to a wide variety of means for producing such forces, for example, in addition to the above mentioned compass and gyro, the apparatus is applicable to an electric current indicating instrument.

Although only two embodiments have been illustrated and described in detail it is to be expressly understood that the invention is not limited thereto. For example, instead of the control element l5 being movable with the longitudinal axis thereof parallel to the filaments I0, Il it is possible for the member to be angularly shiftable about a point, in which case the filaments should be arranged radially thereabout. Also, instead of arranging two conductor elements Ill, II in the recesses 2|, 22 it is possible to employ one or a large number of such elements which may be connected in series or in parallel. Instead of the wedge 34 a simple separating wall may be employed in order to reduce the width of the device. The filaments or conductors are normally of nickel, platinum, or other metal having high resistance temperature coeflicients. However, non-metallic conductors such as copper oxide maybe used, the resistance temperature coefficients of which is greater than that of metal. Mica carriers, for example, can be employed for the copper oxide. The conductors instead of being wires may be in the form of thin bands, the larger surface of the bands permitting a more rapid temperature equalization; and a higher controlling speed than the wires. Various changes may be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art. For a definition of the limits of the invention reference will be had primarily to the appended claims.

What is claimled is:

l. In apparatus of the class described, an electrical bridge circuit having two arms thereof formed of temperature responsive resistor elements, a source of current for said bridge circuit, a source of fluid pressure whose temperature differs from the normal temperature of said resistor'elements, a pair of conduits for normally conveying fluidpressure from said source equally to said resistor elements thereby maintaining said elements at like temperatures whereby said bridge is balanced, said conduits being in communication and forming a fork, a nozzle for directing fluid pressure from said source to said conduits, and a wedge-shaped member whose diverging sides constitute a side for each of said conduits and having an apex thereof disposed in said forked connection opposite said nozzle, said nozzle and wedge-shaped member being relatively displaceable whereby fluid pressure flows unequally from said source through said nozzle to said resistor elements thereby unequally varying the temperature and resistance of said elements whereby said bridge is unbalanced and current flows therethrough.

2. In apparatus of the class described, an electrical bridge circuit having two arms thereof formed of temperature responsive resistor elements, a source of current for said bridge circonveying fluid pressure from said source equally to said resistor elements thereby maintaining said elements at like temperatures whereby said bridge is balanced, said conduits being in communication and forming a fork, a stationary nozzle for directing fluid pressure flow from said source to said conduits, and a wedge-shaped member whose diverging sides constitute a side for each of said conduits and having an apex thereof disposed in said fork connection opposite said nozzle and adapted for movement thereby varying the fluid pressure flow in each of said to said elements thereby maintaining said elements at like temperatures whereby said bridge is balanced, said conduits being in communication and forming a fork, a nozzle for directing 'fluid pressure flow from said source to said conduits and being'adapted for angular movement relative to said conduits, and a stationary wedgeshaped member whose diverging sides constitute a side for each of said conduits and having an apex thereof disposed in said fork connection for normally equallyv directing said fluid pressure to said conduits during a normal position of said nozzle and variably directing said vfluid pressure to said conduits during angular movements of said nozzle whereby the temperature and resistance of said elements is unequally varied and said bridge circuit is unbalanced having current flow therethrough.

4. In apparatus of the class described, an electrical bridge circuit having two arms thereof formed of temperature responsive resistor elements, a housing embodying said elements and having a pair of channels, said channels having a common inlet, a source of fluid pressure Whose temperature differs from the normal temperature of said elements, a nozzle for directing fluid pressure flow to said channels to lmpinge equally upon said elements maintaining the temperatures thereof the same whereby said bridge is balanced, and a wedge-shaped control member Whose diverging sides constitute a side for each of said channels for governing the flow of uid pressure in said channels, the control member having an apex thereof directed against the fluid flow, said nozzle and control member being mounted fory relative movement with respect to each other whereby fluid pressure flow is varied in said channels to thereby unequally vary the temperature and resistance of said elements whereby the bridge is unbalanced and current flows therethrough.v

5. In apparatus of the class described, an electrical bridge circuit having two arms thereof formed of temperature responsive resistor elements, a housing embodying said elements and having a pair of channels, said channels having a common inlet, a source of fluid pressure whose temperature differs from the normal temperature of said elements, a nozzle mounted for angular movement normally directing fluid pressure flow to said channels to-impinge equally upon said elements maintaining the temperatures thereof the same whereby the bridge is balanced, and a stationary Wedge-shaped control member whose diverging sides constitute a side for each of said channels for governing the flow of fluid pressure in said channels, the control member having an apex thereof directed against the fluid flow whereby during angular movement of said nozzle fluid flow is varied in said channels ythereby differentially varying the temperature and resistance of said elements causing unbalancing of the bridge circuit whereby current flows therethrough.

6. In apparatus of the class described an electrical bridge circuit having two arms thereof formed of temperature responsive resistor elements, a housing embodying said elements and having a pair of channels, said channels having a common inlet, a source of uid pressure whose temperature differs from the normal temperature of said elements, a nozzle for directing fluid pressure flow to said channels to impinge equally upon said elements maintaining the temperature thereof alike whereby vsaid bridge is balanced, and a movably mounted Wedge-shaped control member whose divergingl sides constitute a side for each of said channels for governing the flow of fluid pressure in said channels, whereby upon movement of said control member the crosssectional area oi.' said channels is varied so that fluid pressure flow is directed unequally through said channels to impinge upon said elements unequally thereby differentially varying the temperature and resistance of said elements whereby said bridge is unbalanced and current ows therethrough.

PAUL sPEcH'r. 

